Air gap and tripping operation adjustment means for a circuit breaker



Sept. 14, 1965 A. B. MICHETTI 3,

AIR GAP AND TRIPPING OPERATION ADJUSTMENT MEANS FOR A CIRCUIT BREAKER Filed Nov. 7, 1962 2 Sheets-Sheet 1 INVEN TOR. ANT/MM Y 5. 44/66 5777 Sept. 14, 1965 A. B. MICHETTI AIR GAP AND TRIPPING OPERATION ADJUSTMENT MEANS FOR A CIRCUIT BREAKER 2 Sheets-Sheet 2 Filed Nov. 7, 1962 n WE N mm 5 T M M Jr W i M w a w 6 4 P w W 5 k/ M a United States Patent 3,206,576 AIR GAP AND TRIPPING OPERATION ADJUST- MENT MEANS FOR A CIRCUIT BREAKER Anthony B. Michetti, Philadelphia, Pa., assignor to I-T-E Circuit Breaker Company, Philadelphia, Ia., a corporation of Pennsylvania Filed Nov. 7, 1962, Ser. No. 235,928 6 Claims. (Cl. 200-95) This invention relates to circuit breakers and more particularly to a novel magnetic instantaneous trip means having a single means which provides for both air gap adjustment and tripping operation.

Automatic circuit breakers are normally provided with instantaneous trip means which is comprised of a magnetic structure that becomes operative when subject to overload currents of any predetermined magnitude so as to actuate a mechanism which is turn causes a tripper bar to be urged into rotational movement. The tripper 'bar in turn releases a latch mechanism which is held in position to restrain an energized opening spring from moving to its de-energized state. In this condition the circuit breaker contacts are kept in the closed or engaged position. Upon release of the latch mechanism, however, the operating spring is enabled to move from the fully charged to the de-energized state, thereby affording rapid, separating movement of the circuit breaker cooperating contacts. Such tripping operations are designed to function at speeds suificient to interrupt the current in the circuit being protected so as to prevent any harm to befall the elements of the circuit being protected by the circuit breaker, as well as the circuit breaker itself.

The adjustment of the magnetic trip means is selected so as to initiate an instantaneous tripping action during the occurence of a fault condition having a high-current magnitude. Since the magnetic trip means does operate during extremely high-current faults, which may cause severe damage to the equipment being energized by the circuit, it is of the utmost necessity that the tripping operation be both rapid and reliable. It is therefore necessary to provide tripping means which are readily and rapidly adjustable so as to be operative immediately upon the occurence of high-current faults of predetermined magnitudes. In addition to providing such adjustable features, it is also necessary to provide an instantaneous magnetic trip means which is extremely reliable during operation thereof when called upon to initiate a tripping operation so that the equipment energized by the circuit being protected will be isolated from any severe fault current conditions.

Since the circuit breaker may undergo an extremely large number of closing and tripping operations during its useful operating life, the mechanical parts under-go a significant amount of wear. The wearing of these parts may so eiiect both the critical adjustment of the elements of the circuit breaker and the inherent strength of the cooperating elements themselves, as to severely effect both the timing and the reliability of the instantaneous trip means, causing the trip means to fail to operate at the predetermined fault current conditions for which it was originally designed. In addition to providing for adjustment of the instantaneous trip means due to wearing of the breaker elements, it may become necessary to install a circuit breaker in a variety of dilierent applications wherein each individual application has a different faultcurrent condition to which the instantaneous magnetic trip means must be responsive. It is therefore quite advantageous to provide an armature adjustment structure enabling safe, rapid, and reliable adjustment of the magnetic trip means without the necessity for complex tools, or a tedious adjusting operation, whether the adjustment be required for purposes of compensating for wearing of parts, or for adjusting a circuit breaker to react according.

to predetermined tault current conditions.

The device of the instant invention acts to provide all of the above features, while at the same time being constructed so as to be easily operated without the necessity for any complex tools or manual manipulations and is further constructed so as to be comprised of a minimum of parts which are arranged in such a way that the elements of the tripping device provide the dual functions of enabling rapid, reliable adjustment and of providing.

the tripping action under control of a fault currentcondition.

The device of the instant invention is comprised of an adjusting button mounted for rotational movement within the con-fines of a supporting member and having a biasing means which provides the dual function of retaining the adjusting button in the appropriate angular position and restraining the button member from experiencing any linear motion along its longitudinal axis. The first end of the adjusting button is adapted to receive an adjusting tool for imparting rotation thereto. The opposite end of the adjusting button has a cam surface which is so constructed as to cooperate with an elongated adjusting pin member having a first end which abuts the cam surface of the adjusting button. The opposite end of. the adjusting pin is pivotally secured to a movable armature member and under control of the rotation of the adjusting butt-on, the pin member moves the armature member relative to the magnetic instantaneous trip means core member, thereby providing the appropriate air gap adjustment. with a hexagonal head having a tapped aperture for threadedly engaging the threaded end of the elongated pin. Threaded engagement enables a further adjustment to be made so as to provide a second means for control ling the air gap adjustment. The remaining threaded portion of the elongated pin threadedly engages a nut having a knurled peripheral surface enabling rapid movement thereof. The bot-tom surface of the nut abuts against a tripper bar lever arm, causing the lever arm to be moved and subsequently causing the tripper bar to undergo rotation due to the movement of the elongated pin means, which movement occurs at a predetermined magnitude of fault current in the circuit being protected. The tapped aperture in the nut member permits the nut to experience linear movement relative to the pin member, thereby permitting an additional adjustment so as to further control the moment at which the tripper bar rotates sulficiently to release the fully charged spring means in order to cause separation of the circuit breaker cooperating contacts.

The holding bracket and tripping assembly are so designed as to be easily installable in circuit breakers which are presently in use, as well as in new circuit breaker structures, thereby readily adapting themselves for employment in a wide variety of circuit breaker applications and structures. The biasing means, in addition to main- A first end of the elongated pin is provided taining the vertical alignment of the adjusting button member is further constructed to cooperate with a plurality of grooves provided in the upper surface of the adjusting member in order to properly position the magnetic means armature member in a variety of arbitrary angular orientations. The plurality of functions which each element of the adjusting structure provides thereby substantially optimizes the number of elements which comprise the magnetic instantaneous tripping means to a minimum, while at the same time providing a safe, accurate and reliable operating structure. The arrangement is further so constructed as to provide direct movement of the armatrue member in response to movement of the adjusting button member without the necessity of any linkages therebetween. Also, the adjusting button member need only be rotated, either clockwise or counterclockwise, for positioning the armature member and need not undergo any other movement such as for example, longitudinal movement, in order to provide for the adjusting operation.

It is therefore one object of this invention to provide an instantaneous magnetic trip means, which is provided with unitary means for performing the air gap adjustment and the trip initiating operation.

Another object of this invention is to provide an instantaneous magnetic trip means for circuit breakers having a novel adjusting button which is directly connected to the armature member to provide safe, reliable air gap adjustments.

' Still another object of this invention is to provide an instantaneous magnetic trip means for circuit breakers having a cam surface for smoothly and uniformly operating the magnetic means armature member.

Another object of this invention is to provide an instantaneous magnetic trip means for circuit breakers, which includes a unitary pin assembly designed to perform the dual functions of air gap adjustment and trip initiation.

Still another object of this invention is to provide an instantaneous magnetic trip means for circuit breakers having biasing means for performing the dual function of positioning and securing the armature adjustment button and for aligning the armature member in a plurality of predetermined discreet positions.

Another object of this invention is to provide an instantaneous magnetic trip means for circuit breakers, having a novel unitary pin assembly for performing the dual functions of magnetic air gap adjustment and trip initiation and which is further designed to provide additional mechanical adjustment means to compensate for tolerances within the mechanism.

These and other objects will become apparent when reading the accompanying description and drawings in which:

FIGURE 1 is a perspective of an instantaneous magnetic trip means designed according to the principles of the instant invention shown in cooperation with the tripper bar structure of a circuit breaker shown prior to being tripped.

FIGURE 2 is a side view of an instantaneous magnetic trip device showing by dotted lines a side view of important hidden components.

FIGURE 3 is a front view of the instantaneous magnetic trip means of FIGURE 2, which is taken along the phantom line a, a showing a partial cross-sectional view of the instantaneous magnetic trip assembly.

Referring now to the drawings FIGURES 1-3 show an instantaneous magnetic trip means 100 adapted for installation into a circuit breaker assembly [not shown], which is provided with a floor 101 suitable for receiving fastening means 102 which is inserted through an aperture 111 in the instantaneous magnetic trip means housing frame 110. Only very few elements of the circuit breaker assembly have been portrayed in FIGURES 13 for the purposes of clarity but, it should be assumed that the circuit breaker into which the instantaneous magnetic trip means is installed is comprised of a pair of cooperating contacts which may be operated to their open position by both a manual means and at least a magnetic trip means and the manual means may be operable for any purpose while the magnetic trip means is designed to provide a tripping operation upon the occurrence of highmagnitude current faults in the circuit being protected by the circuit breaker. A circuit breaker of this general type is set forth in US. application No. 132,046 entitled Assembly for Circuit Breaker Mechanism filed August 17, 1961, by Wilson W. Poulton, Jr. and assigned to the assignee of the instant invention. A detailed description of such a ciruit breaker is unnecessary for purposes of the instant invention and the aforementioned US. application is thereby incorporated herein by reference.

For purposes of understanding the device of the instant invention suffice it to say that the circuit breaker to be employed is provided with a tripper bar 103 mounted in close proximity to the instantaneous magnetic trip means wherein said tripper bar 103 is mounted to rotate in both a clockwise and counterclockwise direction, as shown by arrows 106 and 107 respectively, such that the tripper bar rotates about its central axis represented by phantom line 104. The tripper bar 103 is biased by means not shown, in the clockwise direction shown by arrow 106, such that the projecting lever 105, extending from the body of tripper arm 103, has its flanged end a in close proximity to the lower surface 140k of adjustable nut member 140, which initiates the tripping operation in a manner to be more fully described. counterclockwise rotation of the tripper bar 103 causes release of the circuit breaker latching mechanism [not shown], which releases the circuit breaker operating spring [not shown], for movement of the circuit breaker cooperating contact [not shown], to their fully disengaged position, thus, terminating current flow in the circuit being protected.

The tripper bar 103, shown in FIGURES 1-3 may be of a length greater than that shown in the figures to allow use of instantaneous magnetic trip means of the type shown by means 100, in conjunction with circuit breakers. Such instantaneous magnetic trip means are used to protect either single-phase or multi-phase electrical distribution systems. The latter systems can be exemplified by the widely used three-phase electrical systems, which are provided with three instantaneous magnetic trip means of the type shown by structure 100. Each instantaneous magnetic trip means protects its individual associated phase of the three phase system.

The instantaneous magnetic trip means 100 is comprised of a frame member 110 which houses all the elements of the instantaneous magnetic trip and air gap adjusting structure, thereby allowing a rapid and simple installation of the apparatus 100 into a circuit breaker housing [not shown]. One manner in which the instantaneous magnetic trip means may be installed into a circuit breaker is to insert a fastening member 102 [see FIGURE 3] through an aperture 111 provided in the base of frame 110 so as to secure the instantaneous magnetic trip means 100 to the floor 101 of the circuit breaker housing. The magnetic trip means is provided with a magnetic flux-generating circuit which is comprised of the multi-winding structure 118, wound upon and suitably insulated from a shaft 114, which passes through the center of the multi-winding structure 118. The shaft 114 is formed of a ferro magnetic material and has secured to it, at its opposite ends, pole pieces 115 and 115a respectively, such that pole pieces 115 and 115a,, in addition to being mechanically secured to shaft 114 provide a complete and substantially U-shaped magnetic path shown by the phantom line 175 in FIGURE 3. The pole pieces 115 and 115a, which lie in close proximity to the outer periphery of the multi-winding assembly 118 are suitably insulated therefrom by insulating sheets a and 17011 respectively, which prevent the windings of multi-winding structure 118 from becoming short-circuited. Frame member 110 is cut so as to provide two inwardly extending tabs 117 and 117a along the opposite side walls of frame 110, which tabs are seated within the grooves 116 and 116a respectively, of the pole piece assemblies 115 and 115a. These tabs act to position and secure the pole pieces 115 and 115a and hence the shaft 114 and the multi-winding structure 118 so that these elements experience no movement whatsoever. The frame member 110 is further provided with suitable apertures on opposite side walls thereof, which apertures 125a and 12511 receive suitable fastening means such as the fastening means 125 [see FIGURE 1] for further securing the magnetic core structure comprised of the pole pieces 115, 115a, the winding 118 and the shaft 114 to the frame member 110. A substantially U-shaped slot 113 is provided along both side walls of frame member 110' which serves to permit relatively rapid installation of the magnetic core assembly since the shaft member 114 may be substantially greater in length than the distance between the interior vertical walls 180 and 181 of the frame member 110 [see FIGURE 3].

The magnetic instantaneous trip means is provided with an armature member 126 having projections 127 and 128 at one end thereof, which projections cooperate with suitable openings 112 and 112a respectively in the side walls of frame member 110 so as to pivotally mount armature member 126 relative to frame member 110. The armature member 126 is biased in the clockwise direction, as shown by arrow 190 in FIGURE 2, due to the first and second bias members 131 and 132, having their first ends 1311) and 1321) respectively hooked into suitable openings [not shown] in the flanges 133 and 134 respectively, provided at the rear of frame member 110. The first ends 131a and 132a of bias members 131 and 132 are hooked to a U-shaped end portion 130 of a substantial L-shaped member 129 which is secured to the underside of armature member 126, in any suitable manner. The lower straight portion 137 of L-shaped member 129 extends through a suitable opening 136 in pin member 135 so as to pivotally secure pin member 135 to armature member 126. The opposite end of pin member 135 is provided with an hexagonally shaped head member 139 having a tapped aperture [not shown] for threadedly engaging the threaded portion 138 provided at the upper end of pin member 135. This head member is rotatable in order to adjust the trip initiation and the air gap, in a manner to be more fully described. A threaded member 176, having a suitable tapped aperture, threadedly engages the threaded upper portion of pin member 135 in order to lock the hexagonally shaped member 139 in any desired position after adjustment thereof. The nut member 140 having a knurled periphery 140a is also threadedly engaged by pin member 135 and upon appropriate rotation thereof may be moved in the upward or downward vertical directions, as shown by arrows 196 and 197 respectively, in order to adjust the trip initiation timing in a manner to be more fully described. A second locking member 177, having a suitable tapped aperture, is threadedly engaged by pin 135 and is provided to lock nut member 140 into any suitable position after appropriate adjustment thereof. Threaded members 176 and 177 may be replaced, if desired, by a sealing compound which is adapted to rigidly secure button 139 and nut member 140 to the pin 135. One advantageous compound which may be employed is sold under the registered trademark Locktite.

The upper surface of frame member 110 is provided with a suitable aperture 191 for receiving the hexagonal head 139 therethrough. Aperture 191 enables the pin member 135 to experience reciprocal motion in the upward and downward vertical directions as shown by arrows 196 and 197, respectively which can be seen in FIGURE 3. This reciprocal motion is directly imparted to the armature member 126 which under control of movement of pin member experiences rotational movement about its pivot points 127 and 128, respectively. Armature member 126 completes a magnetic loop path which is a substantially O shaped or squareshaped path and is comprised of armature member 126, pole pieces 115a, shaft 114, pole pieces 115k and upon return, to the armature member 126. An air gap of predetermined dimensions exists between the left hand end of armature 126 and the upper surface of pole pieces 115a and the similar manner between the right hand end of armature member 126 and the upper surfaces of pole pieces 115b, respectively [see FIGURE 1].

As mentioned previously, biasing members 131 and 132 are adapted to urge armature member 126 in a clockwise direction as shown by arrow 190 of FIGURE 2. An air gap adjustment means is provided for con trolling both air gap adjustment and maintenance of a selected air gap dimension and is comprised of adjusting button 145a having a shaft portion 149 which is adapted to be received by a suitable aperture [not shown] in the upper surface of frame member 110. A tapered pin 151 is staked vertically in the top of the frame member 110. The button 145a has its bottom most portion 150 slipped over the pin 151 and is prevented from vertical motion by the top of the frame 110 and the member 154. This arrangement enables adjusting button 145a to experience rotational movement in either the clockwise or counterclockwise directions. The opposite end of adjusting button 145a is provided with a groove 146 suitable for receiving an adjusting tool such as, for example, a screw driver. There is nothing unique about the way in which groove 146 is arranged and any screw driver will suflice for the adjustment of the adjusting means 145. The adjusting button 145a is provided with a central portion 146 having lower and upper surfaces 148 and 147, respectively. The lower surface 148 is an eccentric or cam surface which rises and dips in a predetermined manner in order to control the vertical positioning of pin means 135 in a manner to be more fully described. The upper surface 147 of adjusting button 145a is provided with a plurality of radially aligned grooves such as, for example, the grooves 156a, 15611 and 1560 which can best be seen in FIGURES 2 and 3. These groves cooperate with a biasing member 152 in order to positively control the angular orientation of adjusting button 145a in a manner to be more fully described.

Biasing means 152 is rigidly secured at its lower end to the side wall of frame member 110 by suitable fastening means 153. The biasing means 152 is substantially L-shaped as can best be seen in FIGURE 1, and is provided with a horizontally aligned portion 154 which is comprised of a first and second arm (only one of which can be seen in FIGURES 1 and 2) wherein each arm is provided with a substantially U-shaped or flanged portion 155 at the end thereof. This U-shaped end portion is designed to be slidably engaged by the grooves 156 through 156a provided on the upper surface 147 of adjusting button 145a in order to provide a positive means for controlling the air gap positions. The biasing member 152 is adapted to impart a force in the downward vertical direction causing the U-shaped portions 155 to bear against the upper surface 147 of adjusting button 145a.

The operation of the instantaneous magnetic trip means is as follows:

In order to set the instantaneous magnetic trip means 100 at any one of a plurality of preselected air gap adjustments: The adjustment button 145a may be rotated in either the counterclockwise or clockwise directions in order to move the pin assembly 135 and hence the armature member 126.

As shown in FIGURE 3 the portion 148a of the cam surface 148 is shown immediately beneath the hexagonal head member 139 secured to pin assembly 135. The biasing means 132 and 131 move armature member 126 and hence pin member 135 in the upward vertical direction as shown by arrow 195. This causes the upper surface of hexagonal shaped member 139 to bear against portion 148a of cam surface 148. Tapered pin 151, however, prevents adjusting button 145a from experiencing any linear movement in either the upward or downward vertical directions thereby causing pin assembly 135 to remain motionless once the upper surface of hexagonal shaped member 139 bears against the cam surface 148 in the manner shown in FIGURE 3. This causes armature member 126 to assume the position shown in FIGURE 3. In this position the biasing member 152 has its U-shaped portion 155 seated in the groove 1560. The downward vertical force of the biasing member 152 which is exerted against the adjusting button 145a prevents button 145a from experiencing any rotational movement thereby maintaining the air gap positioning which is shown in FIG- URE 3.

In order to change the air gap adjustment, adjusting button 145a is rotated either in the clockwise or the counterclockwise direction to a different air gap position. One example is that of rotating adjustment button 145a so the lowermost portion 14811 of the cam surface 148 [see FIGURE 3] is moved to the position occupied by the uppermost surface portion 14811 as shown in FIGURE 3. This would mean an angular orientation of 180 or in other words a one-half turn of adjusting button 145a. In this position groove 156d is moved beneath the flanged end 155 of biasing means 152 thereby locking the adjusting button 145a in the appropriate position.

The movement of portion 1481) of cam surface 143 to a point immediately above the upper surface of hexagonal shaped held member 139 causes pin member 135 to move in the downward vertical direction as shown by arrow 197. This movement is directly imparted to armature member 126 thereby causing a change in the air gap setting between armature 126 and the magnetic core structure of the instantaneous magnetic trip means 100. FIG- URE 3 shows the positioning of the nut means 140 when the adjusting button 145a is shown in the position of FIGURE 3, which position is designated by the numeral 195. When the portion 1485 of the cam surface 148 is moved so that it occupies the position of surface 143a as shown in FIGURE 3 the nut means 140 moves down to the position designated by the number 1%. The same vertical movement is experienced by the lower end of pin member 135 and hence by the armature member 126. Thus in the position shown by numeral 195 the maximum air gap position is attained while the position designated by numeral 1% sets the magnetic trip means at its minimum air gap position. A plurality of positions are obtainable between the minimum and maximum limits 198 and 195, respectively. The adjusting assembly 145 facilitates the adjustment operation by providing the biasing member 115 and the radially aligned grooves 156 through 156d which cause the adjusting button 145a to snap in to the predetermined angular positions determined only by the positioning of the radially aligned grooves 156 through 155d. The cam surface 148 is a substantially smooth surface thereby causing armature member 125 to experience rotation in a very smooth continuous manner.

The tripping operation is performed by the cooperation of the lower surface 140!) of nut member 140 which bears against the edge of flanged portion 105a of arm 105 which is rigidly secured to tripper bar 103.

The instantaneous magnetic trip means is connected in series relationship with the circuit being protected and is provided with a first terminal member 120 having an eyelet 121 for receipt of a leadin conductor of the circuit being protected. Opposite end of terminal member 120 is connected to a conductor 119 which conductor comprises one end of the multi-turn winding structure 118. Opposite end of the multi-turn winding structure 118 has a conductor 122 which extends to one end of the substantially L-shaped terminal member 123 and is secured thereto in any suitable manner. Terminal member 123 is provided with an eyelet 124 which is connected to any suitable conductor means (not shown) which conductor path leads directly to the circuit breaker cooperating contacts (not shown). Thus if a severe fault current of extremely high magnitude occurs in the circuit being protected this current passes through the multiturn winding structure 118 generating an intense magnetic field of high magnitude. This magnetic field is directed through the magnetic members mainly the shaft member 114 and the pole pieces a and 115b, respectively which pole pieces generate a magnetic field in the air gap region of a polarity and magnitude sufiicient to draw the armature member 126 which the pole pieces 115 and 115:: causing armature member 126 to be moved in the counterclockwise direction is shown by arrow 19% in FIGURE 2. This counterclockwise rotation of armature member 126 causes pin member to move in the downward vertical direction as shown by arrow 197 causing the lower surface 14% of nut to bear against the end surfaces 105b of flanges 105a provided on the lever arms 105. The movement imparted to lever arms 105 causes tripper bar 103 to rotate in a counterclockwise direction as shown by arrow 107 at a predetermined moment. Rotation of the tripper bar 103 causes the release of a latch mechanism (not shown) which mechanism is adapted to hold the circuit breaker opening spring means (not shown) in the fully charged position. As soon as this latch mechanism is released the opening spring is free to move the cooperating contacts (not shown) of the circuit breaker to their fully disengaged position, thereby interrupting current flow through the circuit breaker and hence through the circuit being protected. The instant of time at which the tripping operation occurs is controlled in three different manners:

(l) The air gap adjustment of the instantaneous magnetic trip means 100 controls the instant at which the armature member 126 is attracted to the core structure of the magnetic trip means and is controlled by the rotational positioning of the adjusting button a.

(2) Hexagonal shaped head 139 is provided with a suitable tapped aperture which threadedly engages the threads 138 provided on pin member 135 and upon clockwise and counterclockwise rotation as shown by arrows 142 and 141, respectively the hexagonal shaped head member 139 causes pin member 135 to move in either the downward or upward vertical directions thereby providing a second means for controlling the positioning of armature member 126. This adjustment is provided as a fine tuning type of adjustment and accommodates for any possible misalignment in the circuit breaker elements so as to provide further control over the instant of time in which the tripping operation occurs.

(3) Nut member 140 is provided with a tapped aperture which threadely engages the threads 138 on pin member 135 and upon rotation of nut member 140 in either the clockwise or counterclockwise direction. This movement causes nut member 140 to move in either the upward or downward vertical directions thereby controlling the moment at which the lower surface 140a thereof bears against the lever arms 105 to initiate the tripping operation. The hexagonally shaped member 139 and the nut member 140 once having been adjusted to any chosen position may be locked in this position by their accompanying locking members 176 and 177 respectively which are tightened against the head member 139 and the nut member 140 causing these members to remain in their chosen positions. The hexagonal shape of the head member 139 land the knurled surface 140a of nut member 140 facilitate the handling of these members.

It can therefore be seen that the adjusting button 145a is so designed as to directly impart movement to the armature member 126 under control of the rotation of adjusting button 145a. The pin means 135 further performs the function of controlling the air gap adjustment providing further adjustments for any misalignment due to the slight imperfection of the circuit breaker elements and finally performs the function of initiating a tripping operation. Since all of these functions are incorporated into a single pin assembly this arrangement provides a safe reliable, instantaneous magnetic trip means while reducing the number of elements of the trip means to a minimum amount. The design of the trip means 100 is such that it is readily adaptable to any existing circuit breakers as well as circuit breakers which have not yet been built and further requires only some tripper bar arrangement which undergoes either rotational or some reciprocal movement in order to control the tripping operation of the circuit breaker assembly in which the instantaneous magnetic grip means is employed.

Although I have described preferred embodiments of my novel invention, many variations and modifications will be obvious to those skilled in the art, and I prefer therefore to be limited not by the specific disclosure herein but only by the appended claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. Instantaneous magnetic trip means for use in circuit breakers having tripper bar latch releasing means comprising a magnetic core assembly including winding means for generating a magnetic field of a magnitude proportional to the current passing therethrough; movably mounted armature means positioned in close proximity to said core assembly and adapted to form a substantially closed loop magnetic fiux loop; a reciprocally mounted tripper pin assembly having a first end pivotally linked to said armature; a rotatably mounted air gap adjustment means, said adjustment means having a cam surface, said cam surface being adapted to impart linear movement to said pin assembly responsive to rotation of said adjusting means; trip initiating means positioned along said pin assembly intermediate the ends thereof for imparting rotational movement to a tripper bar assembly when said armature is urged towards said core assembly upon the occurrence of a severe fault current of a predetermined magnitude.

2. Instantaneous magnetic trip means for use in circuit breakers having tripper bar latch releasing means comprising a magnetic core assembly including winding means for generating a magnetic field of a magnitude proportional to the current passing therethrough; movably mounted armature means positioned in close proximity to said core assembly and adapted to form a substantially closed loop magnetic flux loop; a reciprocally mounted tripper pin assembly having a first end pivotally linked to said armature; a rotatably mounted air gap adjustment means, said adjustment means having a cam surface, said cam surface being adapted to impart linear movement to said pin assembly responsive to rotation of said adjusting means; trip initiating means positioned along said pin assembly intermediate the ends thereof for imparting rotational movement to a tripper bar assembly when said armature is urged towards said core assembly upon the occurrence of a severe fault curent of a predetermined magnitude; the second end of said pin assembly opposite said first end being adapted to slidably engage said cam surface.

3. Instantaneous magnetic trip means for use in circuit breakers having tripper bar latch releasing means comprising a magnetic core assembly including winding means for generating a magnetic field of a magnitude proportional to the current passing therethrough; movably mounted armature means positioned in close proximity to said core assembly and adapted to form a substantially closed loop magnetic flux loop; a reciprocally mounted tripper pin assembly having a first end pivotally linked to said armature; a rotatably mounted air gap adjustment means, said adjustment means having a cam surface, said cam surface being adapted to impart linear movement to 10 said pin assembly responsive to rotation of said adjusting means; trip initiating means positioned along said pin assembly intermediate the ends thereof for imparting rotational movement to a tripper bar assembly when said armature is urged towards said core assembly upon the occurrence of a severe fault current of a predetermined magnitude; the second end of said pin assembly opposite said first end being adapted to slidably engage said cam surface; said pin assembly second end including an adjustable member slidably engaged by said pin assembly for adjusting the positioning of said armature member relative to said core assembly.

4. Instantaneous magnetic trip means for use in circuit breakers having tripper bar latch releasing means comprising a magnetic core assembly including winding means for generating a magnetic field of a magnitude proportional to the current passing therethrough; movably mounted armature means positioned in close proximity to said core assembly and adapted to form a substantially closed loop magnetic flux loop; a reciprocally mounted tripper pin assembly having a first end pivotally linked to said armature; a rotatably mounted air gap adjustment means, said adjustment means having a cam surface, said cam surface being adapted to impart linear movement to said pin assembly responsive to rotation of said adjusting means; trip initiating means positioned along said pin assembly intermediate the ends thereof for imparting rotational movement to a tripper bar assembly when said armature is urged towards said core assembly upon the occurrence of a severe fault current of a predetermined magnitude; said trip initiating means being linearly movable relative to said pin assembly to adjust the timing of the trip initiating operation.

5. Instantaneous magnetic trip means for use in circuit breakers having tripper bar latch releasing means comprising a magnetic core assembly including Winding means for generating a magnetic field of a magnitude proportional to the current passing therethrough; movably mounted armature means positioned in close proximity to said core assembly and adapted to form a substantially closed loop magnetic flux loop; a reciprocally mounted tripper pin assembly having a first end pivotally linked to said armature; a rotatably mounted air gap adjustment means, said adjustment means having a cam surface, said cam surface being adapted to impart linear movement to said pin assembly responsive to rotation of said adjusting means; trip initiating means positioned along said pin assembly intermediate the ends thereof for imparting rotational movement to a tripper bar assembly when said armature is urged towards said core assembly upon the occurrence of a severe fault current of a predetermined magnitude; biasing means having an ear portion adapted to bear against said air gap adjustment means; said adjustment means having a plurality of radially aligned grooves cooperating with said biasing means ear portion to align said armature in a plurality of predetermined discrete positions.

6. Instantaneous magnetic trip means for use in circuit breakers having tripper bar latch releasing means comprising a magnetic core assembly including winding means for generating a magnetic field of a magnitude proportional to the current passing therethrough; movably mounted armature means positioned in close proximity to said core assembly and adapted to form a substantially closed loop magnetic flux loop; a reciprocally mounted tripper pin assembly having a first end pivotally linked to said armature; a rotatably mounted air gap adjustment means, said adjustment means having a cam surface, said cam surface being adapted to impart linear movement to said pin assembly responsive to rotation of said adjusting means; trip initiating means positioned along said pin assembly intermediate the ends thereof for imparting rotational movement to a tripper bar assembly when said armature is urged towards said core assembly upon the occurrence of a severe fault current of a predetermined magnitude; the second end of said pin assembly opposite said first end being adapted to slidably engage said cam surface; armature biasing means positioned to urge said armature in a first direction away from said core assembly; said adjustment means being adapted to restrain movement of said armature in said first direction within predetermined limits.

References Cited by the Examiner UNITED STATES PATENTS 1,140,433 5/15 Ames 2()O166 12 2,997,551 8/61 Kinsman 200166 FOREIGN PATENTS 1,079,177 4/60 Germany.

BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. INSTANTANEOUS MAGNETIC TRIP MEANS FOR USE IN CIRCUIT BREAKERS HAVING TRIPPER BAR LATCH RELEASING MEANS COMPRISING A MAGNETIC CORE ASSEMBLY INCLUDING WINDING MEANS FOR GENERATING A MAGNETIC FIELD OF A MAGNITUDE PROPORTIONAL TO THE CURRENT PASSING THERETHROUGH; MOVABLY MOUNTED ARMATURE MEANS POSITIONED IN SLOCE PROXMITY TO SAID CORE ASSEMBLY AND ADAPTED TO FORM A SUBSTANTIALLY CLOSED LOOP MAGNETIC FLUX LOOP; A RECIPROCALLY MOUNTED TRIPPER PIN ASSEMBLY HAVING A FIRST END PIVOTALLY LINKED TO SAID ARMATURE; A ROTATABLY MOUNTED AIR GAP ADJUSTMENT 